Database session driver fails

Switching the session driver from 'file' to 'database', I get these two errors:

ErrorException in EncryptCookies.php line 123: Argument 1 passed to Illuminate\Cookie\Middleware\EncryptCookies::encrypt() must be an instance of Symfony\Component\HttpFoundation\Response, instance of Illuminate\View\View given, called in /var/www/servmon0/vendor/laravel/framework/src/Illuminate/Cookie/Middleware/EncryptCookies.php on line 59 and defined

FatalErrorException in View.php line 394: Uncaught exception 'BadMethodCallException' with message 'Method [send] does not exist on view.' in /var/www/servmon0/vendor/laravel/framework/src/Illuminate/View/View.php:394 Stack trace:..........

Why? Any idea?

Note: I work with Laravel 5